Conventional memory or storage devices have the basic components of a writing and reading device and a storage medium. The storage density of a storage device is determined by the size of a basic storage unit which can store one bit of data. This size is determined by the resolution of the writing and reading device which modifies the storage medium and retrieves the stored data.
One can easily imagine that the ultimate limit of a surface storage density is one bit of data per surface atom, and this limit provides an enormously higher storage density than any conventional storage devices. The realization of this limit requires both a writing and reading device with atomic resolution and a storage medium with a storage unit of atomic scale.
It is therefore an object of the present invention to provide a memory device having an ultra high storage density.
It is a further object of the present invention to provide a memory device which utilizes intrinsic surface atoms of a substrate as data storage units.